Improve GNU readline compat, patch by Steve Tell in 1997 and 1998

This changeset adds support for:
   * rl_prep_terminal(),
   * rl_deprep_terminal(), both of which are only wrappers to rl_ttyset().
   * rl_getc()

and:
   * (*rl_getc_function), defaults to rl_getc()
   * (*rl_event_hook)
   * (*rl_prep_term_function), defaults to rl_prep_terminal()
   * (*rl_deprep_term_function), defaults to rl_deprep_terminal()

For further details, see http://www.cs.unc.edu/~tell/dist/magic-readline.README

Differences from Steve's commit include: signal safety in rl_getc(), restart
read() on EINTR, and make sure to support "int meta_flag" to rl_prep_terminal()
which is the GNU syntax.  To that end I reused the inverse of rl_meta_chars.

include/editline.h

@@ -30,14 +30,14 @@ typedef enum {
 typedef char* (*rl_complete_func_t)(char*, int*);
 typedef int (*rl_list_possib_func_t)(char*, char***);
 typedef el_status_t (*el_keymap_func_t)(void);
+typedef int  (*rl_hook_func_t) (void);
+typedef int  (*rl_getc_func_t)(void);
+typedef void (*rl_voidfunc_t)(void);
+typedef void (*rl_vintfunc_t)(int);
 
 /* Display 8-bit chars "as-is" or as `M-x'? Toggle with M-m. (Default:0 - "as-is") */
 extern int rl_meta_chars;
 
-/* Use these functions to set custom command/file completion, see cli.c for example usage. */
-rl_complete_func_t    rl_set_complete_func(rl_complete_func_t func);
-rl_list_possib_func_t rl_set_list_possib_func(rl_list_possib_func_t func);
-
 /* Editline specific functions. */
 void el_bind_key_in_metamap(char c, el_keymap_func_t func);
 
@@ -59,4 +59,12 @@ extern void add_history(const char *line);
 extern int read_history(const char *filename);
 extern int write_history(const char *filename);
 
+rl_complete_func_t    rl_set_complete_func(rl_complete_func_t func);
+rl_list_possib_func_t rl_set_list_possib_func(rl_list_possib_func_t func);
+
+void rl_prep_terminal(int meta_flag);
+void rl_deprep_terminal(void);
+
+int rl_getc(void);
+
 #endif  /* __EDITLINE_H__ */

src/editline.c

@@ -63,6 +63,11 @@ typedef struct {
     char      **Lines;
 } el_hist_t;
 
+rl_getc_func_t rl_getc_function = rl_getc;
+rl_hook_func_t rl_event_hook;
+rl_vintfunc_t  rl_prep_term_function   = rl_prep_terminal;
+rl_voidfunc_t  rl_deprep_term_function = rl_deprep_terminal;
+
 /*
 **  Globals.
 */
@@ -109,6 +114,7 @@ int               rl_meta_chars = 0; /* Display 8-bit chars as the actual char(0
 char             *rl_line_buffer;
 const char       *rl_prompt;
 const char       *rl_readline_name;/* Set by calling program, for conditional parsing of ~/.inputrc - Not supported yet! */
+FILE             *rl_instream;
 
 /* User definable callbacks. */
 char **(*rl_attempted_completion_function)(const char *token, int start, int end);
@@ -196,11 +202,20 @@ static void tty_push(int c)
     el_push_back = c;
 }
 
+int rl_getc(void)
+{
+    int r;
+    char c;
+
+    do {
+	r = read(0, &c, 1);
+    } while (r == -1 && errno == EINTR);
+
+    return r == 1 ? c : EOF;
+}
+
 static int tty_get(void)
 {
-    char c;
-    int r;
-
     tty_flush();
     if (el_pushed) {
         el_pushed = 0;
@@ -208,12 +223,8 @@ static int tty_get(void)
     }
     if (*el_input)
         return *el_input++;
-    do
-    {
-        r = read(0, &c, 1);
-    } while (r == -1 && errno == EINTR);
 
-    return r == 1 ? c : EOF;
+    return rl_getc_function();
 }
 
 #define tty_back()       (backspace ? tty_puts(backspace) : tty_put('\b'))
@@ -280,6 +291,20 @@ static void tty_info(void)
 }
 
 
+/*
+**  Glue routines to rl_ttyset()
+*/
+void rl_prep_terminal(int meta_flag)
+{
+    rl_meta_chars = !meta_flag;
+    rl_ttyset(0);
+}
+
+void rl_deprep_terminal(void)
+{
+    rl_ttyset(1);
+}
+
 /*
 **  Print an array of words in columns.
 */
@@ -1104,7 +1129,7 @@ char *readline(const char *prompt)
     }
 
     tty_info();
-    rl_ttyset(0);
+    rl_prep_term_function(!rl_meta_chars);
     hist_add(NILSTR);
     ScreenSize = SCREEN_INC;
     Screen = malloc(sizeof(char) * ScreenSize);
@@ -1129,7 +1154,7 @@ char *readline(const char *prompt)
         tty_flush();
     }
 
-    rl_ttyset(1);
+    rl_deprep_term_function();
     free(Screen);
     free(H.Lines[--H.Size]);
 

src/sysunix.c

@@ -43,7 +43,11 @@ void rl_ttyset(int Reset)
 
         new = old;
         new.c_lflag &= ~(ECHO | ICANON | ISIG);
-        new.c_iflag &= ~(ISTRIP | INPCK);
+        new.c_iflag &= ~INPCK;
+	if (rl_meta_chars)
+	    new.c_iflag |= ISTRIP;
+	else
+	    new.c_iflag &= ~ISTRIP;
         new.c_cc[VMIN] = 1;
         new.c_cc[VTIME] = 0;
         if (-1 == tcsetattr(0, TCSADRAIN, &new))
@@ -76,7 +80,12 @@ void rl_ttyset(int Reset)
 
         new = old;
         new.c_lflag &= ~(ECHO | ICANON | ISIG);
-        new.c_iflag &= ~(ISTRIP | INPCK);
+        new.c_iflag &= ~INPCK;
+	if (rl_meta_chars)
+	    new.c_iflag |= ISTRIP;
+	else
+	    new.c_iflag &= ~ISTRIP;
+
         new.c_cc[VMIN] = 1;
         new.c_cc[VTIME] = 0;
         if (-1 == ioctl(0, TCSETAW, &new))
@@ -121,9 +130,10 @@ void rl_ttyset(int Reset)
         new_sgttyb = old_sgttyb;
         new_sgttyb.sg_flags &= ~ECHO;
         new_sgttyb.sg_flags |= RAW;
-#ifdef PASS8
+	if (rl_meta_chars)
+	    new_sgttyb.sg_flags &= ~PASS8;
+	else
 	    new_sgttyb.sg_flags |= PASS8;
-#endif
         if (-1 == ioctl(0, TIOCSETP, &new_sgttyb))
 	    perror("Failed TIOCSETP");
         new_tchars = old_tchars;